Decomposition of NH ₃ and Subsequent Combustion in an Integrated Ru-/Pt-Catalytic Microreactor

Ammonia is a promising carbon-free fuel, but its use is limited by high ignition temperature and NO x emissions. This work proposes an integrated microreactor using a sequential decomposition–combustion strategy for clean power generation from pure ammonia. Ru-coated microchannels first drive endothermic NH 3 decomposition, producing an H 2 –N 2 mixture that then burns in a central channel. Kinetic analysis shows Ru-catalyzed decomposition outperforms gas-phase reactions and exhibits nonmonotonic pressure dependence. A plug-flow reactor network confirms that coupling Ru-catalyzed decomposition with Pt-catalyzed combustion greatly improves NH 3 conversion and N 2 selectivity while suppressing NO x . A two-dimensional model further shows that Pt in the combustion channel enhances heat recirculation and markedly reduces NO emissions by lowering gas temperature and limiting thermal NO x formation. The integrated microreactor offers a compact, efficient route to ultralow-NO x ammonia-based power systems.